1. Field of the Invention
This invention relates to probe heads and, in particular, to probe heads utilizing the mechanism of attenuated total reflectance for use in infra-red spectroscopy.
2. Description of Related Art
Attenuated total Reflectance (ATR) crystals use the total internal reflectance to effect an interaction between a sample and beams of radiation of wavelengths suitable for infra-red spectroscopy.
Total internal reflection occurs when the crystal material is optically denser (i.e. has a greater refractive index) than the surrounding medium, provided that the angle of incidence .alpha..sub.1 fulfills a certain condition.